Rotary Cutter Gearbox...What to use?

Iplayfarmer · May 23, 2006

I just got my old used rotary cutter up and running. Now a few questions about lube in the gearbox.

What should I use to top off my rotary cutter gear box?
Does universal tractor fluid work?
Do I need to drain and change this fluid periodically?
How full should the gearbox be?

Iplayfarmer · May 23, 2006

I just got my old used rotary cutter up and running. Now a few questions about lube in the gearbox.

What should I use to top off my rotary cutter gear box?
Does universal tractor fluid work?
Do I need to drain and change this fluid periodically?
How full should the gearbox be?

beenthere · May 23, 2006

I'd get a sample of what is in there first, and check it for 'dirt' and stiffness. Sometimes, heavy gear oil is used and on occasion, people put grease in them (as in grease-gun grease). Check for water as well. Then you can decide if you can get by adding gear oil or if you should drain it out and begin with new gear oil.
Usually there is a plug on the side of the box to check the oil level. Look for a steel plug with a 1/4" square head (pipe plug) that you can remove. If the gear oil is at that height, it is ok. I'd be careful not to tighten that plug REAL tight, as they can be a b**** to get out and don't need to be much more than finger tight.

beenthere · May 23, 2006

I'd get a sample of what is in there first, and check it for 'dirt' and stiffness. Sometimes, heavy gear oil is used and on occasion, people put grease in them (as in grease-gun grease). Check for water as well. Then you can decide if you can get by adding gear oil or if you should drain it out and begin with new gear oil.
Usually there is a plug on the side of the box to check the oil level. Look for a steel plug with a 1/4" square head (pipe plug) that you can remove. If the gear oil is at that height, it is ok. I'd be careful not to tighten that plug REAL tight, as they can be a b**** to get out and don't need to be much more than finger tight.

Highbeam · May 23, 2006

My gearbox uses 90 weight gear oil. Not UTF. If there's water in it, you'll get a nice grey/brown milkshake right away. If you see the milkshake then change the oil. You can remove the fill plug and then tip the mower over on its side to drain it out. The gearbox doesn't hold much oil and it won't hurt a thing to change it. If you are going to change it I would run it and get all the sediment stirred up first so that it comes out with the old oil.

Highbeam · May 23, 2006

My gearbox uses 90 weight gear oil. Not UTF. If there's water in it, you'll get a nice grey/brown milkshake right away. If you see the milkshake then change the oil. You can remove the fill plug and then tip the mower over on its side to drain it out. The gearbox doesn't hold much oil and it won't hurt a thing to change it. If you are going to change it I would run it and get all the sediment stirred up first so that it comes out with the old oil.

rdbrumfield · May 23, 2006

I run a bush hog, 6ft, and it calls for 90wt. Lost the lower seal many years ago, replaced it and filled with a good grease. I put some 90 in with it and drilled a small hole in the filler plug to vent. Haven't had a problem with it, and I use it regularly, and hasn't leaked since.

rdbrumfield · May 23, 2006

I run a bush hog, 6ft, and it calls for 90wt. Lost the lower seal many years ago, replaced it and filled with a good grease. I put some 90 in with it and drilled a small hole in the filler plug to vent. Haven't had a problem with it, and I use it regularly, and hasn't leaked since.

coffeeman · May 28, 2006

My mower manual asks me to check oil each day before using. I guess it makes sense. However, there is no dipstick on gear box and I would have to remove plug on side each day to check oil. I have a Woods 990-3. A pain in the rear but .... oil is cheaper than bearings and gears. Does anyone know an easier way to check oil; maybe I could add a dipstick?

Cheers....Coffeeman

coffeeman · May 28, 2006

My mower manual asks me to check oil each day before using. I guess it makes sense. However, there is no dipstick on gear box and I would have to remove plug on side each day to check oil. I have a Woods 990-3. A pain in the rear but .... oil is cheaper than bearings and gears. Does anyone know an easier way to check oil; maybe I could add a dipstick?

Cheers....Coffeeman